Vitamin C at a dose of 50 mg actually supports the absorption of non-heme iron, as it converts iron into a form that is more easily absorbed in the intestine (Cook, Reddy, 2001), so the combination with vitamin C makes sense and has a scientific basis. However, for raspberry leaf extract there is no specific evidence of an effect on iron status or athletic performance, so you should regard it mainly as an additional component rather than a key part of the formula. Iron deficiency is fairly common among female athletes and can affect performance (PMC, 2025, Iron deficiency in female athletes), so it's worthwhile to have your ferritin monitored by a doctor regardless of the product chosen.

For this product, we recommend that you definitely consult a doctor or gynecologist before use. Raspberry leaf extract (Rubus idaeus) is often advised against in early pregnancy in traditional use, as it is believed it may stimulate uterine contractions, although this is a traditional rather than strictly clinically proven warning. Since pregnant women generally need significantly more iron (up to about 27 mg/day) (NIH ODS, 2025), it's also possible that your doctor will recommend a product without added plant extracts. Iron and vitamin C alone in this product are not problematic ingredients; caution mainly applies to the raspberry leaf extract.

Direct claims about increasing VO2 max from taking iron are not supported by sufficiently solid evidence to be guaranteed as an expected outcome, so it makes sense to be cautious about such claims. It is documented that iron plays a role in oxygen transport via hemoglobin, and that correcting an actual deficiency in athletes can improve endurance performance, while supplementation in individuals without a deficiency generally provides no additional benefit (PMC, 2023, The IRONy in Athletic Performance). If you train intensely and suspect low ferritin, it's best to verify this with a lab test rather than relying solely on supplementation.

This is indeed a gap for this product – for sports supplements, where the absence of prohibited substances also matters, the gold standard is a certification such as NSF Certified for Sport, or at least a publicly published independent laboratory report per batch (NSF International). We did not find such publicly available documentation for this product, which means purity and the absence of contaminants or banned substances cannot be independently verified. If you compete in organized sport with doping testing, we recommend checking additional documentation with the brand before use, or choosing a product with certified testing.